As described in U.S. application Ser. No. 09/675,677, filed Sep. 29, 2000, by Leo J. Campbell et al. and titled SYSTEMS AND METHODS FOR AUTHENTICATING AN ELECTRONIC MESSAGE, the disclosure of which is expressly incorporated herein by reference, an electronic postmark, or EPM, provides content and temporal integrity and identification authenticity for data, which is transferred over a network. Such EPMs have traditionally been used to authenticate the identity of the sender of a particular message or to authenticate the time/date at which the message was created. Increasingly, however, not only the identity and time/date of creation are important, but also the physical or geographic location of the sender of the message is significant.
Authenticated location or geographic information may be used for many purposes, including, for example, being able to establish with a certain degree of confidence the location at which a particular message or data was created. But, as noted above, the present systems and methods do not permit that. Accordingly, there exists a need for electronic postmarking of location or geographic data.